One of the fundamental tradeoffs in program design is between volume and intensity. Volume provides training specificity, practicing the fundamental movement patterns of the athlete’s sport. Intensity forces adaptation, preparing the athlete to perform at a high level. High volume protocols are necessarily lower in intensity; high intensity protocols typically require regular “deloading” periods to allow adequate recovery. While typical endurance training programs already use two to three interval workouts per week, the effect of higher intensity interval workout blocks has not been studied extensively.
For endurance athletes, two of the key parameters determining performance are VO2 max and oxygen cost. In lay terms, VO2 max measures the athlete’s ability to transport and use oxygen, while oxygen cost measures how much oxygen is consumed for a given effort. While VO2 max is strongly correlated with performance in all endurance athletes – cross-country skiers, runners, and cyclists alike – previous work observed that elite cyclists have relatively low VO2 max compared to other endurance athletes, but relatively low oxygen cost. Roughly stated, they aren’t able to take in as much oxygen, but don’t need as much, either.
In light of this observation, Øyvind Støren and co-workers at Telemark University College, in Norway, hypothesized that a high intensity running protocol could improve VO2 max for an elite cyclist.1 Using running for some portion of this cyclist’s training was attractive from a practical standpoint – in a cold climate like Norway’s, the weather is often more compatible with running than with cycling – but would the reduced training specificity offset any gains?
The test protocol, described in more detail in the cited paper, inserted two blocks of high intensity running intervals into the cyclist’s pre-season workouts. The first block, which took place in November 2010, included 14 interval sessions in 9 days. The second, which took place in January 2011, included 15 interval sessions in 10 days. In between, and for the remainder of the pre-season program, the cyclist followed a typical program with a high volume of low to moderate intensity training, with 3 cycling interval sessions per week.2
In interpreting the results, it is important to remember that the test subject was already elite, having competed at the Norwegian national level for three years. A less experienced cyclist might not have the recovery capacity to tolerate the high intensity training blocks. Indeed, the researchers observed that the test subject was showing signs of over-reaching by the end of the high intensity blocks. A less experienced cyclist might also suffer more setbacks due to the reduced training specificity, not having built as sound a training foundation.
For the test subject, however, the results were impressive. Time trial performance improved by 14.9%, a very substantial gain for someone already at the elite level. VO2 max and lactate threshold also improved, while time trial heart rate dropped and pedal cadence increased.3
As the researchers point out, caution must be used when extrapolating these results to other athletes or other sports. The results do seem to support the idea that at least some portion of an endurance athlete’s training should take place at higher intensity and reduced volume. However, both recovery and training specificity concerns suggest that moderate intensity, high volume training periods are important as well. A natural next step would be to test similar high intensity protocols with a larger group.
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